Trencher with adjustable stabilizer bar

ABSTRACT

A trancher of the endless bucket or rotary wheel type has an adjustable crumbing stabilizer. The stabilizer is adjusted vertically by means of a chain and sprocket arrangement, the sprocket being fixed to the digger frame and the chain being fixed at both ends to the stabilizer. An hydraulic braking device is used to hold the stabilizer in adjusted position.

United States Patent Heckathorn [11] 3,787,989 [451 Jan. 29, 1974 1 1 TRENCHER WITI-I ADJUSTABLE STABILIZER BAR I [75] lnventor: Loyd E. Heckathorn, Garden Grove,

Calif.

[73] Assignee: Towner Manufacturing Company,

Santa Ana, Calif.

22 Filed: July 17, 1972 [2]] Appl. No.: 272,238

[52] US. Cl. 37/90, 37/97 [51] Int. Cl E02f 3/12 [58] Field of Search 37/83, 8690, 94-97 [56] References Cited UNITED STATES PATENTS 1,038,915 9/1912 Lyback 37/90 969,187 9/1910 Poulter 37/86 1,911,615 5/1933 George 37/94 2,714,262 8/1955 Malzahn 37/86 1,039,412 9/1912 Kessler 37/95 3,022,585 2/1962 Bradley.; 37/90 X 421,122 2/1890 Carter 37/94. 3.690.023 9/1972 Peterson l 37/90 2,584,287 2/1952 Przybylski 37/90 2,747,307 5/195'6 Griffin 37/90 FOREIGN PATENTS OR APPLICATIONS 1,094,128 12/1967 Great Britain 37/86 1,079,481, 8/1967 Great Britain 37/97 Primary Examiner-Robert E. Pulfrey Assistant Examiner Clifford D. Crowder Attorney, A gent, or Firm Nienow & Frater [5 7] ABSTRACT A trancher of the endless bucket or rotary wheel type has an adjustable crumbing stabilizer. The stabilizer is adjusted vertically by means of a chain an'dsprocket arrangement, the sprocket being fixed tothe digger frame and the chain being fixed at both ends to the stabilizer. An hydraulic braking device is used to hold the stabilizer in adjusted position.

5 Claims, 8 Drawing Figures UKTENTED JAN 29 m4 SHEET 1 OF 2 FIG.3

TRENCHER WITH ADJUSTABLE STABILIZER BAR BACKGROUND It is well known that an ever increasing number of elements such as pipes, utility cables, conduits, wires, etc. are being placed underground for (A) improving the overall appearance of the neighborhood; and (B), to a limited extent, for protecting the buried elements against external damage. To achieve this burial procedure, it becomes necessary to dig a trench of the desired depth, width, length, and configuration; to pile the removed soil along side the trench; to bury the continuous or interconnected elements in the trench; and to then back fill the trench with the previously removed soil.

These trenching operations are generally performed by a machine known as a Trencher; but present day trenchers have a number of serious drawbacks. One of the most serious of these drawbacks is the fact that the resultant trench does not have a smooth, level bottom; so that when burying fairly rigid or brittle elements, such as tile pipes or the like, the trench bottom must often be further processed before use.

Thus, while prior art trenchers are fairly satisfactory, there is a need for an improved trencher.

OBJECTIVES AND DRAWINGS It is therefore the principal objective of the present invention to provide an improved trencher.

It is another objective of the present invention to provide an improved trencher that maintains a horizontal orientation.

It is still another objective of the present invention to provide an improved trencher that provides an improved trench depth.

It is a further object of the present invention to provide an improved trencher that produces an improved trench bottom.

. It is a still further objective of the present invention to provide an improved trencher that provides trencher leveling.

It is a. still further objective of the present invention to provide an improved trencher-that minimizes trencher bounce and tooth chattering.

The attainment of these objects and others will be realized from the study of the following description and drawings of which:

FIG. 1 shows a pictorial view of a trencher having a digger and a stabilizer;

FIG. 2 shows an enlarged view of the digger and stabilizer;

FIG. 3 shows a view of the stabilizer bar;

FIG. 4 shows a side cross section view of a chain belt drive;

FIG. 5 shows a top cross sectional view of a chain and a chain belt drive;

FIG. 6 shows a side view of the stabilizer bar and its guide and movement arrangement;

FIG. 7 shows a top view of the guide arrangement for the stabilizer bar; and

FIG; 8 shows another type of digger and stabilizer.

' SYNOPSIS Broadly speaking, the present invention discloses a trencher having a stabilizer mounted thereon; the

stabilizer having a stabilizer bar whose foot portion is maintained in contact with the bottom of the resultant trench. The improved results are achieved by providing apparatus for moving the stabilizer bar in a vertical direction; the vertical stabilizer bar movement being of small increments. A motor and a suitable linkage are described for moving the stabilizer bar and the stabilizer foot.

INTRODUCTION The Basic Trencher The basic trencherwill be understood from FIG. I. This illustration shows a trencher 10 that is comprised of a crawler having a pair of spaced apart caterpillar tracks 12 that carry chassis upon which is mounted an engine l3; a side mounted operators seat 14 that gives the operator an obstructed view of the operations; a

plurality of trenching accessories and their ancillary apparatus; and a set of hand and foot operator controls 15 for controlling the trenching operations. Thus, the operator can by means of control 15 control the various trenching accessories and the movement of trencher 10, which may thereupon move to the right or to the left at any of a plurality of controllable speeds.

Trencher Accessories I 7 One of the above mentioned trenching accessories is a back fill blade 16 that may be angled and/or raised and lowered to permit the operator to level high spots, to clear a path ahead of the trench, to later refill the trench, etc.

Another one of the trenching accessories is a digger 17 that is mounted on the trencher l0, and comprises a plurality of interhinged transverse buckets l8 having replaceable teeth on the digging edges of the buckets this type of digger being known, because of its appearance, as a ladder type digger.

The toothed buckets 18 of digger 17 are adapted to rotate on the digger framework in the direction indicated by the arrows. This digger rotation generally has a plurality of selectable speeds that are independent of the trenchers road speed; and one of the most satisfactory ways of producing such a bucket rotation is by the use of adigger rotor gear, such as-20, that drives a pair of internally toothed digger driven gears 21 that rotate around a suitable number of idler gears.

The movement of the toothed buckets l8 is such as to cause their teeth to bite into the ground; and to thus free volumes of soil that are collected by associated buckets.

The soil that is collected by the buckets 18 is carried upwards by the upward movement of the buckets; and when the buckets 18 are tilted at the top of their travel, they drop their contained soil onto a high speed conveyor belt 23; so that the spoil may be deposited on either side of the trench. This feature becomes very convenient when materials or obstacles are positioned along side the proposed trench; the reversal of the conveyor belt permitting the spoil to be deposited wherever most convenient.

It should be--noted, in-'passing, that buckets 18 are available in a variety of sizes. Moreover, a variety of bucket teeth is also available for use with different types of soil. In addition, the buckets and/or bucket teeth may be so mounted that various bucket sequences" are available; for example, in a three bucket sequence a first bucket may be used to cut one area of the trench, a second bucket may be used to cut a second area of the trench, and a third bucket may be used to trim and clean up the entire trench this triad of buckets being followed by similar triads.

In FIG. 1, the digger 17 is indicated to comprise a digger framework that maintains the buckets 18 in an operative relation; the digger framework being adapted to be vertically raised or lowered by the operator controls 15. In FIG. 1, the digger 17 is indicated to have its lowermost buckets 18 positioned above ground level; the vertical movement of the digger 17 being accomplished by the use of arms 24 that are, in turn, activated by means such as power cylinders 25.

While the various trencher accessories may be powered in any desired manner (e.g., electrically, pneumatically, hydraulically, etc.,) it is found most convenient to use hydraulic power throughout, for all of the trencher accessories.

Trencher Operation In one mode of trencher operation, the operator progressively lowers the digger 17; so that as sequential ones of the moving toothed buckets l8 occupy the lowermost position, their teeth engage the ground, and each bucket 18 thus removes an individual volume of soil. Thus, the digger produces a substantially vertical hole.

In another mode of operation, when a trench (a longitudinal hole rather than a vertical hole) is desired, the operator causes the trencher to move to the right as indicated by the arrow of FIG. 2. As the operator causes the trencher 10 to move along a guide line, the digger and its rotating toothed buckets 18 produce a longitudinal trench 26 of the desired width, depth, and configuration; the spoil being deposited along side the trench for later refill operations.

The ladder type trencher is ideal for close work; since the operator may place the vertical sides of the trench or hole flushto buildings, curbs, pipes, and other obstacles and can produce trenches with square corners, suitable curvatures, etc. In many cases, such a ladder type trencher is able to produce holes and trenches that are 6 feet deep or, in certain cases even deeper.

It is of course desirable to dig the trench as fast as possible; and among the reasons for this desire is the fact thatthespeed of finishing the trench eliminates the cost of barricades, lanterns, and the like; removes the danger of open trenches; removes the problem of dirt running back into the trench; etc. As a result, the operator tries to have the toothed buckets take as large a bite of soil as possible; and this leads to the following undesirable effects. I

Depending upon various conditions e.g., the longitudinal speed of the trencher, the rotational speed of the toothed buckets, the sharpness of the teeth, the p nclitign and yp 9f grpqricl; We W951). f ozen, rocky, etc.) 44 a'plurality' of teeth are either biting into or releasing their engagement with the ground either simultaneously, separately, alternately, or sequentially. This complex intermingling of tooth actions produces a bouncing of the trencher and a chattering of the teeth; and causes the entire trencherto tip from its normal horizontal orientation onto the proximal ends of the caterpillar tracks. The overall result is that the teeth wear out unduly quickly; there is a continuous shocking of the apparatus and the operator; and the trench is of uneven depth and bottom contour this latter consideration being particularly undesirable when a rigid type floor.

DISCLOSURE The Stabilizer The disclosed trencher overcomes these problems as follows. Referring back toFlG. 1, it will be seen that the trencher 10 has a stabilizer 30 that may be affixed to the trencher 10, or to the digger 17, by a stabilizer mounting 31 that may be welded or otherwise fastened. When the stabilizer 30 is affixed to the digger 17, the stabilizer 30 is automatically raised and lowered along with the raising and lowering of the digger 17.

Stabilizer 30 comprises a stabilizer bar 33 that may be independently raised and lowered by means such as a hydraulic motor 34 having suitable hydraulic fluid conduits 35. Thus, by means to be more fully discussed later, the stabilizer bar 33 is infinitely adjustable (i.e., is adjustable in an infinite number of minute increments) in its vertical relationship with the digger 17 and thus with the trencher 10. I

It will be further noted that stabilizer bar 33 has a foot portion 37; and FIG. 2 shows how the stabilizer 30 and the stabilizer bar 33 enter into the operation of the trencher 10.

The Stabilizer Bar As indicated in FIG. 2, the stabilizer bar 33 has been positioned vertically to such a position that the sole ,of

its foot portion 37 is substantially flush with the bottom 38 of the trench 26. With the stabilizer bar 33 in this position, the stabilizer 30 provides a number of important advantages. First of all, it provides additional support and stabilization for the trencher 10; so that the trencher 10 is better able to maintain a stable horizontal orientation, and to thus obviate the prior art trencher tilting. Second, the stabilizer 30 helps support the weight of the trencher; and absorbs the down pressure of the cutting teeth. Third, the teeth maynow take bigger bites of soil; and thus work faster. Fourth, stabilizer 30 tends to permit the teeth to maintain a more consistent angle of attack; thus leading to longer tooth life. Fifth, the stabilizer 30 tends to counteract the trencher bounce and tooth chatter. Sixth, each cutting section of the digger now cuts a similar, uniform slice. Seventh, the trencher 10 may now work in soils that range from hardrocky ground to wet and sticky soil. Eighth, the trencher is now enabled to cut a trench of more uniform depth, with a smoother bottom. 7

Another important advantage of the stabilizer results from the capability of the operator to continually vertically re-position the stabilizer bar 33 in extremely small increments relative to the trencher; and this advantage will be understood from the following discussion.

Assume that the trencher 10 is cutting a trench in the manner described above. If the soil changes, for example, to a more rocky formation, the teeth will tend 'to bite in; thus tending to tilt the trencher although this trencher tilting will be greatly minimized and limited by the action of the stabilizer bar foot portion 37 pressing against the bottom of the trench. In the present case, the operator may slightly re-position the stabilizer foot by suitable activating the motor 34; so that the trencher quickly resumes the desired trenching operation for the particular ground formation. Thus, the operator may continually re-position the stabilizer bar 33 so that the teeth take optimal bites out of the soil.

Thus, the instant response of the stabilizer enables the trencher to hold the desired digging depth and bottom contour; and the operator has an additional way to cause the trencher to produce a trench whose depth is under precise and positive control, and whose trench bottom is therefore level.

The Stabilizer Foot The stabilizer foot may be designed primarily for thestabilizing action described above. Furthermore, its heel portion may be additionally designed for gathering up the'dirt crumbs 39 that fall back into the trench, so that the buckets may carry these crumbs out of the trench, and to the surface. Moreover, the sole of the stabilizer foot may be designed to smooth out and/or compact the bottom of the trench.

Thus, the trencher operates in a more consistent manner; does a better job; and provides an improved trench in a shorter time.

FIG. 3 shows a rear view of the stabilizer bar 33 and its foot portion 37. In this illustration, the stabilizer bar 33 and its foot 37 are indicated to have the same width as the trench; so that the trailing, toe portion of the foot 37 aids in the smoothing and compacting of the trench bottom.

As indicated above, the digger buckets 18 (not shown in FIG. 3) are available in various sizes; and the size of the stabilizer bar 33 and/or its foot portion 37 may be selected to stabilize the trench, and/or to smooth the trench bottom, and/or to smooth the trench side's.

It will be recalled from the discussion presented above in connection with FIGS. 1 and 2, that the stabilizer mounting 31 is preferably affixed to the vertically positionable digger l7; and while the digger is not shown in FIG. 3,'the other illustrated parts of the trencher are identified by the same reference characters as were used in the earlier description. I

In FIG. 3, it may be visualized that the digger (not shown) has been suitably positioned; and that the stabilizer bar 33 has been vertically moved with respect thereto in order that its foot portion 37 may be flush with the bottom of the trench.

Stabilizer Bar Positioning As pointed out above, it is desirable to be able to move the stabilizer bar 33 by extremely small increments, either upwards or downwards; and it has been found that this result is most advantageously obtained by means of a reversible motor 34 of FIGS. 1, 2, and 3. While motor 34 may be connected to the stabilizer bar 33 in a number of different ways, it has been found convenient to use the following overall approach.

in FIG. 4. A shell 45 protectively encloses a driving gear 42, the chain belt 43, the driven gear 44, etc.

FIG. 5 shows that the above mentioned driven gear 44 is afi'ixed to a rotatable shaft 46 that is suitably journaled in bearings such as 47; and that an output gear 48 is affixed to shaft 46 a. chain 49 being wrapped around the output gear 48 (see FIG. 6).

In FIG. 6, suitable alignment gears 50 help'to align the chain 49 on the stabilizer bar 33; the ends of the chain 49 being affixed, as by bolting, to the ends of the stabilizer bar 33. Recapitulation of Stabilizer Bar Positioning In recapitulation, it may be seen that as the motor 34 is actuated to rotate in a given direction, this rotation operating through the reduction gearassembly 40 causes revolution of the output gear 48, whose revolution causes the engaged chain 49 to move the stabilizer bar 33 a predetermined amount in a given direction, under the control of the operator. Thus, the operator may continually reposition the stabilizer foot 37 at the bottom of the trench.

Stabilizer Bar Braking It was pointed out above that the reduction gear assembly causes the stabilizer bar 33 to maintain its vertical position despite the back pressure produced by the trenching operation. However, under some conditions it may be desirable to omit the reduction gear assembly; and in this case the stabilizer bar 33 may be held against vertical movement by means of a brake although the brake may be usedin addition to the re duction gear assembly, if so desired.

Part of the brake arrangement may be seen in FIG. 4, wherein adisc type brake pad 51 is positioned in such a manner that it may be pressed against a portion of the driven gear or against a suitable braking surface. In actuality, the brake arrangement is of the caliper type that has two such opposed brake pads; and both of these brake pads 51 may be seen in FIG. 5. This illustration also indicates that the brake pads 51 are actuated by hydraulic pressure applied through conduit 52.

In this way, the stabilizer bar 33 is braked to hold its desired position during the trenching operation; but is released during the bar-positioning interval. Stabilizer Bar Guides .It was pointed out above that the stabilizer bar 33 was adapted to move upward or downward. In order to These figures show the motor 34 to be linked toa re- A duction gear assembly 40, that may have a step down ratio of about 20:1; this step down ratio having the primary advantage that extremely small foot movements may be thus obtained. A secondary advantage of the reduction gear assembly 40 is that the reverse 1:20 mechanical advantage of the reduction gear assembly prevents the stabilizer foot 37 from being moved upward by the down pressure producedduring the dirt removal action.

In the cross sectional view of FIG. 4, the motor 34 (not visible due to its location) operates through the reduction gear assembly 40; whose output shaft 41 is keyed to a driving gear 42 the driving gear 42 being linked, as by means of a continuous chain belt 43, to a driven gear 44;, is enclosed in a shell 45 that is best seen achieve smooth movement of the stabilizer bar 33, FIG. 6 shows it to use a plurality of guide rollers 54 that ride in U-shaped channel like portions 55 of the stabilizer bar 33, to guide thernovement of stabilizer bar 33; roller brackets 56 being used to provide the desired firmv ness and spacing.

FIG. 7 illustrates a top view of the guide structure; opposed guide rollers 54 being positioned by their respective roller brackets 56, and fitting into respective U-shaped channel like configurations of the stabilizer bar 33.

The chain 49 is indicated to bepositioned between the stabilizer bar 33 and the stabilizer mounting 31, as

discussed above. Wheel Type Trencher The trencher 10 described above has been indicated to have a ladder type bucket arrangement; this arrangeare times when another type of bucket arrangement, known as a wheel type arrangement is desirable; this wheel type bucket arrangement having the advantage that it is somewhat simpler, is lower in overall heighth, and is somewhat easier to transport.

Such a wheel type trencher is shown in FIG. 8; and it will be noted that the primary difference is that the toothed buckets 18 are fixedly attached to the driving gear 21; and that the stabilizer bar 58 preferably takes an arcuate form, rather than the previously discussed linear form. Other than these differences, the stabilizer may be similar to that described above; and operates in a similar manner.

Kits are available for mounting either ladder type or the wheel type diggers on a given trencher.

SUMMARY The present invention has a number of important advantages over prior art trenchers. First of all, it provides additional support and stabilization for the trencher; so that the trencher is better able to maintain a stable horizontal orientation, and to thus obviate the prior art trencher tilting. Second, the disclosed apparatus permits the teeth to maintain a more constant angle of attack; thus leading to a longer tooth life. Third, the stabilizer absorbs the down pressure of the cutting teeth. Fourth, the stabilizer tends to counteract the trencher bounce and tooth chatter by immediately absorbing the biting action of the teeth. Fifth, the trencher may now take bigger bites of soil; and may thus work faster. Sixth, the trencher is now enabled to cut a trench of more uniform depth and improved bottom contour. Seventh, the stabilizer foot may be designed primarily for stabilizing action. Eighth, the stabilizer foot may be additionally designed for gathering up the crumbs of dirt that fall back into the trench; so that the buckets may carry the crumbs of dirt out of the trench, and to the surface. Ninth, the stabilizer foot may be designed to smooth out the bottom of the trench. Tenth, the trencher may now work in soils that range from hard rocky ground to wet sticky soil. Eleventh, each rotation of the diggerapparatus now cuts a uniform slice of soil. And, finally, the trencher now operates in a more consistent. manner; does a better job, and provides an improved trench in a shorter time.

What is claimed is:

1. A trencher comprising in combination, frame means affording an endless path, digging means movably mounted on said frame to follow said endless path, stabilizing means for said trencher comprising mounting means fixed relative to said frame and a stabilizing element adjustably mounted on said mounting means, drive means for adjusting the position of said stabilizing element on said mounting means comprising a drive sprocket on said mounting means and a chain mounted on said element and engaging said sprocket, said drive means further including motive power means for rotating said sprocket to move said chain and thereby said stabilizing element relative to said mounting means, and braking means for holding said element in fixed position on said mounting meanscomprising a hydraulic operator to apply braking force to said element and to remove such braking force as desired.

2. A trencher according to claim 1 wherein said chain has opposite end portions fixed to said element and an intermediate portion engaging said drive sprocket.

3. A trencher according to claim 2 wherein said mounting means comprises rollers engaging said stabilizing element for permitting vertical rectilinear movement of said element relative to said mounting means.

4. A trencher according to claim 1 wherein said braking means comprises at least one frictional braking element controlled by said hydraulic operator.

5. A trencher according to claim 4 wherein said drive means comprises a drive gear operatively interposed between said motive power means and said sprocket and said braking meanscomprises two oppositely disposed frictional braking elements controlled by said hydraulic operator for frictionally gripping said drive gear in response to said hydraulic operator.

an a: a: n 

1. A trencher comprising in combination, frame means affording an endless path, digging means movably mounted on said frame to follow said endless path, stabilizing means for said trencher comprising mounting means fixed relative to said frame and a stabilizing element adjustably mounted on said mounting means, drive means for adjusting the position of said stabilizing element on said mounting means comprising a drive sprocket on said mounting means and a chain mounted on said element and engaging said sprocket, said drive means further including motive power means for rotating said sprocket to move said chain and thereby said stabilizing element relative to said mounting means, and braking means for holding said element in fixed position on said mounting means comprising a hydraulic operator to apply braking force to said element and to remove such braking force as desired.
 2. A trencher according to claim 1 wherein said chain has opposite end portions fixed to said element and an intermediate portion engaging said drive sprocket.
 3. A trencher according to claim 2 wherein said mounting means comprises rollers engaging said stabilizing element for permitting vertical rectilinear movement of said element relative to said mounting means.
 4. A trencher according to claim 1 wherein said braking means comprises at least one frictional braking element controlled by said hydraulic operator.
 5. A trencher according to claim 4 wherein said drive means comprises a drive gear operatively interposed between said motive power means and said sprocket and said braking means comprises two oppositely disposed frictional braking elements controlled by said hydraulic operator for frictionally gripping said drive gear in response to said hydraulic operator. 